It's a balmy London day and I’m sitting comfortably in a black cab, but, for the purposes of demonstrating his new ride sharing app, Maaxi boss Gabriel Campos wants me to envisage a more typical travel scenario.

“Just imagine you’re waiting at the bus stop in the freezing cold and the next one’s not coming for 20 minutes,” he says. Not too much of a stretch, that. “Instead of waiting, you can tap into Maaxi and it gives you a departures board listing the black cabs nearby and how many seats are available in them. That way you have a choice of how many will be in your cab and how much you’ll pay. You can pay for just your seat rather than the whole taxi.”

With the system only going live today, I can’t yet see how many would like to help pay for my jaunt around the Square Mile, but Campos flips through the app to show me how it works.

As well as tapping in where you are and where you’re going to, Maaxi asks how many – up to six – are travelling and whether you’re happy with a mixed ride, or female or male only. The “departures board” (pictured left) then gives a list of potential rides, how far off they are, and how much the ride will cost. The more people join in, the cheaper the fare gets.

The app is aimed at turning black cabs into public transport

Around 2,500 drivers are so far using the app

So far, so good. And, despite the very high-tech mapping system developed to make this work, it seems simple to use. Our driver, Martin, assures me it’s a doddle for him too. The journey is like any other cab ride – albeit with less stress from meter watching.

The app is being used in black cabs - or red cabs, when decked out in Maaxi livery

But what if I don’t like the person next to me? What if they’re really drunk and obnoxious?

“Well we can’t always guarantee you’ll like the person you share a cab with,” says Campos. “But all the rides are trackable and drivers can refuse to let people in. At night I’d say that’s a safer option than the bus.”